Run featureWriters from CLI

similar to #470 but for featureWriters. Also useful for testing/debugging.

Lib/ufo2ft/featureWriters/__main__.py

@@ -0,0 +1,48 @@
+import argparse
+from io import StringIO
+import logging
+
+from fontTools.misc.cliTools import makeOutputFileName
+
+from ufo2ft.constants import FEATURE_WRITERS_KEY
+from ufo2ft.featureCompiler import FeatureCompiler
+from ufo2ft.featureWriters import loadFeatureWriterFromString, logger
+
+try:
+    import ufoLib2
+
+    loader = ufoLib2.Font
+except ImportError:
+    import defcon
+
+    loader = defcon.Font
+
+logging.basicConfig(level=logging.INFO)
+
+parser = argparse.ArgumentParser(description="Apply feature writers to a UFO file")
+parser.add_argument("--output", "-o", metavar="OUTPUT", help="output file name")
+parser.add_argument("ufo", metavar="UFO", help="UFO file")
+parser.add_argument(
+    "writers",
+    metavar="WRITER",
+    nargs="*",
+    help="list of feature writers to enable",
+)
+
+args = parser.parse_args()
+if not args.output:
+    args.output = makeOutputFileName(args.ufo)
+
+ufo = loader(args.ufo)
+writers = [loadFeatureWriterFromString(w) for w in args.writers]
+compiler = FeatureCompiler(ufo, featureWriters=writers or None)
+compiler.setupFeatures()
+buf = StringIO()
+compiler.writeFeatures(buf)
+ufo.features.text = buf.getvalue()
+
+if FEATURE_WRITERS_KEY in ufo.lib:
+    del ufo.lib[FEATURE_WRITERS_KEY]
+
+logger.info("Written on %s" % args.output)
+ufo.save(args.output)